Using Releasy

It really does nothing else than to automate the process outlined above. (Note: Might not be updated for the latest .app yet)

Troubleshooting

If the app does not start, the OS X Console app is your friend. Open it using Spotlight, start your game and look for any errors that appear.

If Console does not show enough information, open a Terminal and cd into the same directory in which the .app file is located. Then run YourGame.app/Contents/MacOS/RubyGosu\ App.

If it seems that everything is correct, but the app still does not start, try compressing it into a .zip file, deleting the .app, and unpacking the .zip file again. This will force OS X to forget any information that it may have cached about the app. (This is sometimes necessary for OS X to recognise changes made to the Info.plist file.)

Using bundler is a little hairy because the structure of the .app folder predates it. You might need to ask on the forum, or use releasy which understands bundler.

If you need to use libraries that are not included in the .app, copy them into the lib folder. If you need C extensions that are not included in the .app, you should ask on the Extending Gosu board.